Motor control.



J.D.IHLDER. MOTOR 001mm.

APPLICATION FILED 0O'I'.11, 1905. 1,005,221. Patented 00111111911. 1

77% 63.5% I W W M firm-"I11 J.-D. IHLDER.

MOTOR CONTROL. APPLICATION PIIIBD 0031.11, 1905. 1,005,221. Patented00131.0,1911.

' 2 QHEETS-SKEET 2.

@hvcnhr/ D Gil-M trolling provision of simple j slowing downalternating-current induction -circuit," by introducing resistance in=lowering the Voltage of.

" speed, in order to gives; uick UNITED srlrrns PATENT OFF CE.

JOHN D. IHLDER, OF NEW YORI N. Y., ASSIGNOR TO OTIS ELEVATOR COMPANY, 01

JERSEY LCITY, NEW JERSEY,

A CORPORATION OF NEW JERSEY.

MOTOR ooN'rRoL.

Specification of Iletters Patent.

: -To all whom it may concern: I

Be it knownthat'I, JOHN D. IHLDER, a citizen of the United States,residing at 1; TNew York city, in the county of New York ti and State ofNew York, have invented a new and useful Improvement. in Motor Control,of which the following is a speci-' My invention relates to means forconelectric motors, particularly such motors as are adapted for theoperation of elevator, hoisting apparatus, but it is applicable to thecontrol of motors in general.

One of the objects of my invention is the 15 provision of -an artificialpower-consuming device of anelectric motorsubstantially the same reducedspeed.

' A further object of my invention is the and efficient means for toeffect a quick reduction of all loads motors by the use ofpower-consuming de- -v1'ces and'means for controlling suchdevices.

f1. Qtherobjects of my invention will ap- 125,;p'ear hereinafter,

V the novel combinations of elements being pointed out in the claims.

Referring to the drawings, Figure 1 illustrates diagrammatically thecircuits and connections of the apparatus embodying my in- *vention' andas applied to an electric elevator System; and Fig. 2 represents amodification thereof. v c Induction motor speed may be varied byintroducing a resistance in the main liifi'e t e [rotor circuit, or bythe supply circuit on condition that the motor does work, but if inelevator work lowering of the load -drives the motor for- 40 l-wardthese".means will be unavailable. I

prefer, therefore, to employ an artificial power-consuming device to bebrought into gactionlsimultaneously with a resistance device'. ,Thispower-consumlng. device may be amechanical frlct-ion brake, a'rotarypump,

a-moto'r which runs unexcited for full speed and is excited only-whenslow speed is deinanded, or any other like device. In any eventit isdesirable that the power-consum o0 in'gidevice should. vary its powerwith its reduction Of from a high speed to;

by a reversing switch "Motor-controlling circuits an Patented Oct. 10,1911.,

the motor from'high speed and "to'bring'jall loads ,ito substantially"the-same reduced speed. The power-consuming, devices ma; be controlledby a hand rope, wheel, switch push-button with single-phase ormultiphasej: &c. In the drawings I have inns-j, Figs. 1 and 2, respectively, aseries- I f magnets, trated in connected direct current generator andauxiliary induction motor, as power-consum ing devices foraccomplishingthe function desired,

While my invention imay be embodied in I difierent forms and isapplicable to different uses, I have illustrated it in connection- 1with the control of a: motor of an elevator,

Or h'oist,'in this instance'the motor I being shown as a multiphaseinduction motor, the direction of rotation of which is controlled{ B andthe acceleration and retardation of which is controlled byanelectro-magnetic switch C 1 The motor may be connected in any suitableman-H. I nor to Operate the car C, the mechanical.

connections for so operating the car being omitted for the 's'akejo'fsimplicity, it being understood that according to the direction ofrotation of themotor the car is moved up apparatus or down alongsuitable stations, which'ma are provided whereby the operation of themotor and the travel of the car maybe con- '85" 4:, 5, and 6 for the];77 a a 1O the contacts the direction of the current 4 the controllingcircuits either the down m g-;

net D or up magnet i move the armature 38 to one side or the U will beenergized other of the center and complete the circuits L of the motorin a rotate asdesired.

the contacts 9, 12 and binding post 4.- is never, reversed but the"ren'iaining connections 5 to the binding. posts 6 and Sfare reversedaccording to the movements of ;.'the SWltQh. B3,,

direction to cause it to, Ihe connection between complete a circuit toeither the up magnet solenoid U or the down magnet solenoid D and isshown here in connection with a direct-current circuit, which whenavailable is preferable for the operation of electric elevators,although alternating-current circuits and magnets can be used ifnecessary. In this instance (2 designates the positive lead, in branchesof which are arranged the solenoids U and D, the return wires beingconnected to the contacts of switch E. Con- ,nection is made from thepositive lead d to contact 30of the reversing switch B while a magnet Lcontrolling the rotor-circuit controller C is connected to contacts 31and 32 on switch B so that as said switch is operated the circuit ofmagnet L will be closed to operate the controller C and also the switch.S. The up magnet U actuates reversing switch B to close the circuits ofthe stator to start the motor in the desired direction to move the carupwardly. The starting of the motor is, however, controlled byadditional apparatus embodied in the starting switch 0 which in thisinstance is that disclosed in my Patent No. 742,031, Oct. 20, 1903,electrical cont-rolling apparatus. Any other suitable starting switchmay be used, however, this form being shown here, for illustration only.

After themotor has been operated the car may be slowed down and stoppedat any time by the operation of the switch E. It will be seen that thisswitch comprises two short aroshapcd contact strips 33 and and also twolonger arc-shaped contact strips 85 and 86. NVhen the switch lever 71 ismoved to the right or left it firet engages one of the longer contactstrips which has the effect of closing the circuits to one of thereversing switch magnets. The reversing switch B will therefore beoperated to close the circuits of thestator of the induction motor I butonly suflicient current is admitted to the stator to prevent backwardrotation of .the motor because the maximum starting resistance isconnected in the rotorcircuit. When the reversing switch is thus closed,contact 30 is moved into contact with either of the fixed contacts 31 or32, thereby connecting the plusxlead cl through'wire 74 to thesolenoid-L, but the circuit is not completed to the minus lead cl sincethe lever 71 is iii engagement with only the longer cont-act strip 85 or86. Upon a further movement of the lever 71, however, the'contact 33 or65 is engaged to effect the energization of the solenoid L. The plungerwill now be lifted, the switch S openedand the resistances R, Rgradually cut out from the rotor circuit.

The power-consuming device hereinbefore referred to comprises in thisinstance a series-wound generator G whose field F and armature A areconnected in series with the switch S by means of suitable circuits. Thei switch S 'comprises fixed contact strips 35 and 36 and a movablebridge piece 3% which is rigidly connected by the stem 29 to the core 75of the magnet L. As soon as the lever 71 is placed 'in one of itsextreme positions, the reversing switch B is operated to ment of thearmature A which is mounted on an extension of the rotor shaft of theinduction motor I, as the external circuit of the generator G isinterrupted at the switc S.

and adapted to be controlled thereby is an Mounted adjacent thereversing switch B additional switch for reversing the armature of theseries wound generator G. This swltchcomprlses a sliding rod 3 mounted1n the bearings 22 and 23 and provided with laterally extending lugs 2and 3 which are 7,

adapted to be engaged by the pin 1 extending to the right from thearmature 38. Ex-

tending from the central portion of the rod 3 is a contact-carrying arm24 on which are mounted the contacts 16 and 17 These 0011- tacts mayengage either the fixed contacts 19, 18, respectively, or the contacts21, 20, respectively. The direct-current generator reversing switchmakes the connection for this generator in correct relation with theinduction motor connection and consequent direction of rotation of theinduction motor. It should be noted that with this arrangement thedirect-current generator connections at its reversing switch are notbroken when the alternating-current motor reversing switch assumes itscentral or open-cir-v cuiting posltlon. For lnstance, 1f the 'up magnetU is operated, the contacts 16, 17 engage the contacts 19, 18,respectively, and i when said magnet is deenergized the revers-- 111gswitch B 15 opened but the contacts 16 and 417 are not moved. The lattercontacts will be again moved only when the down-V magnet D is operated,in which case the 0011- tacts 16, 17 will engage the contacts 21, 20, fa respectively, to reverse the armature A. of

the generator G. i

In order to slow down the induction motor I, the switch lever 71 in thecar is moved toward central position so as to disengage said lever 71and either the'contact 33 or 65 as the case may be. The circuit throughthe solenoid L will thus be interrupted but the circuit through one ofthe reversing switch magnets is still maintained through the contactstrip 85 or 86 and the lever 71 which is connected to the negative main.The plunger 7 5 no longer; being held up by the solenoid L will slowlydescend toeti'ect a gradual introduction of the resistances R,

R in circuit with the rotor of the induction If the contacts 16, l7arein engagement with the contacts 21 and 20, respectively,

' when the induction motor 1, operating in must be traced from the.armature A- I 27, etc.,

the opposite direction, is desired to be slowed down, it is, obviousthat the direction of the current through the armature A will bereversed, for in this-case, the circuit through wire 25 and thencethrough contacts 21 and 16 and by way of Wires37 and 28 to the fieldcoil F. "It is 'necessaryto reverse the armature of the series generatorG for the reason that the induction motor I rotates 'in' one directionto move the car upwardly, and in the opposite direction to move the cardownwardly. The residual magnetism in the series generator G must bekept the same, Whether the said generator is supplying current to thecircuits 26, in one direction or another. That is, the polarity of thepoles of the seriesgenerator G must be 'kept the same and this isaccomplished.

tion'of the armature A is changed with that of the rotor of theinduction motor I. If the car is stopped and then started again, andmoved in the same direct-ion as before, obviously, it is not necessaryto change the connections of the armature A, so the series generatorreversing switch is'left in the same position as before. The slowingdown of the induction motor, I may also be accomplished automatically bymeans of the switches 66 and 67 which are. respectively connected to thecontacts 33 and and to wire 78 at 77. The switch67 may be opened by thecar itself'or by some: part of the hoisting mechanism as the carapproaches a predeterminedpcint in its upward travel.

37, contacts 35, 36 and byreversing the armature A connections when thedirection of rotaof the auxiliary moto In a similar manner switchautomatically operated; to a slow 7 down the 1 car when 1t approaches a(predetermined.

point in its downward; travel. .Ineithcr.

case it is evident thatjtheinagnetL de'elnergized, I thus effectingre-injsei-ugn,

of the resistances R, sin the riotor .otor

circuits and the closing of the.s w-itch "S -of.

.a a mhe ev e i the generator 7 still remains n e1thergof 'li s aextreme pos tions. Iliave'also proyidedautomaticlim e k yi ist-ing' switches69 and 7 0 ,wlienopen the car or by some part, of ti mechanism willeffect a automatic of the car at its limitspfrgtrav heswitch 69 isconnected to contact-:{str 5 and by wire 76 to the .downemagnetwD-,--.ahdi;theg

switch is connectedggto the ,c.ontact;.8 6 and the lip-magnet U.

tor circuits, while 70 will eficct the successively to slow down andstop-the fcar at its upper limit of travel. 1"

In Fig. 2 I have shownniyinvention ap plied to the circuits and "5.0 areoperated Dh;e-.. pen .ng@ f witchv. 69 will thereforehavegithecfiectlof,dni-w gizing the'magnet-D and breaking. the, motheropening" of the switch, denergization A of the mag -J net U and alsothe breakinggof the. motor. circuits. Preferablyaithe switches661511161." 69 are operated successively td'slow'idown. and stop the carat its-lower limitiof -travei: while the switches 67?- and connection'sof -the-' apparatus illustrated iIijFig. l of my Patent titled Electriccontrollingapparatus ;,.but

this is done by way ofillustratihgmyinvem' tion, as it may be applied toother systemsthan that shown in 'said' 'pa'tenti-f desired.

An auxiliary induction motO'r 'QompriSingF a squirrel-cage armature "57and-* aistator winding 58 is directly-connected" by means of the shaft56'to the rotor of thefl induction' motor J. The stator w inding -58 is'co'n; nected in parallel with the stator winding of the main motor J,being corin'c'tedto the motor terminals 4,21 42 and 43. The statorwinding 58,-

in this 'fiii'stancej, j shown star-connected, but the-- commonconnecting:

point is extended. to "thejsw'itchfSY" fwhichis normally closed, but spened as soon as the induction motor J 1s induction motor w hoistingmechanism When it is desired J; the switch S is""'p matically closed ask v are again inserted ingu e rot induction-motor J.

nter te It should be noted, that "j the, connections e i erchanged or, tnit-9 i h dneti ii. xihary .m'o'tors 'cormec gether with the connecmotor J and the au tions are such that this auxiliary motor e615Thfefauxiliary I thereforea free. while the motor J iscpemtearemov thein the. desired direction; t lowdown? the inotpri th les st llccsflit, 5

tends to rotate reversely to the induction motor when the switch S isclosed. In this insta e, the connections between the mains an the statorof the induction motor J as well as those ofithe stator 58 are changedby the reversing switch K but other means'may be used for securing areversal of the auxiliary induction motor when the main motor isreversed. For example, the connections of the auxiliary motor may bemade by a special switch as that shown in Fig. l for reversing theseries generator G, in which case the auxiliary motor could be keptenergized to slow down the main motor even after the circuits to thelatter motor have-been entirely interrupted.

As explained in the patent last referred to, the two' windings D E areprovided with two cores F G. These cores are rigidly connected with eachother and are provided with the contact arm H which is adapted to travelover the contacts I for cutting in and out the resistances R R in therotor circuit of-the elevator motor J. Also connected with the cores FG! so as to move therewith is the stem 29 the upper end of which carriesthe bridge piece 34 forelectrically connecting the contacts 35 and 36.The contacts 35' and 36 and the bridge piece 34' are connectedrespectively by the wires 59,-60 and 61 to the stator winding :58 of theauxiliary induction motor. I

J isshown-in Fig. 2 as a three phase motor of the induction type, andtwoof the 'phases'are led to the windings D"'"and E of the switchmagnet, one phase passing through the winding D and another through thewinding E, so that there is always magnetism in one or the other of thewindings for maintaining the armature F or G attracted, and thus cuttingout the resistances R R from the rotor circuit. The motor-J may be anysuitable alternating-current motor.

I K represents a reversing switch for the motor, the armature L of whichis connected. to be controlled by the up magnets u and down-magnets (2,each of which magnets u and 6?? comprises two alternate currentwindingslVI N and O P. One winding of each magnet is connected to receive onephase of the alternating current supply, and the other winding isconnected to receive another phase, so that when the armature L of theswitch K has been attracted there will always 'be magnetism in one ofthe windings of magnets 10 or (Z to maintain the said core attracted andprevent chattering and consequent noise and loss of chicicncy.

a 7) (2 represent the alternating current supply mains. Q represents-thecar diagrammatically, provided with a switch Sw comprising the handlever T and contacts V, 62 and 62; The contacts V are so concar forraising and lowering the car from the motor.

In the operation of the apparatus, if the lever T of the switch Sw bemoved to its extreme right-hand orleft-hand position so the insulatedcontact 63 will connect the contacts 62 or 62 a circuit will be com:

pleted from the main a, upon which one phase of the current isimpressed, through contacts V, winding N of magnet u,-and back to thecommon return 6. A circuit will also becompleted from the main 0 uponwhich another phase of the alternating current-is impressedthroughcontacts V and winding M of magnet u and back to the common return 5Thus the windings M and N of magnets at each receive a different phaseof the current and the armature L of the reversing swit-chK will beattracted, thereby completing the circuits to the motor for causing itto rotate in a direction to move the car upwardly. When the armature Lis attracted by magnet a, one circuit will be completed from the main a,through contacts 39 and 40 to binding-post 41 on the motor; anothercircuit will be completed from the main 0, through the contacts 44 and45 to the binding-post 43 on the motor; and the third will be completedfrom the common return Z), through contacts 46 and 47 to thebinding-post 42 on the motor. TV hen the armature L is attracted bymagnet (Z, the circuit for the common return Z) to the binding-post 42on the motor is completed as before, but now through contacts 46 and 48;but the connections to binding-posts 41 and 43 are reversed, for acircuit is completed from the main o through contacts 39and 49 tobinding-post 43, and another circuit is completed from the main 0,through contacts 44 and 50 to binclingpost,4l, thus causing the motor torotate in the opposite direction and move the car downwardly.

Thestator windings 58 of the auxiliary induction motor'being alsoconnected to the binding-posts 41, 42 and 43 will also have two of itswindings reversed whenever the elevator motor J is reversed. Theauxiliary motor has its stator windings so connected that. when theswitch S is brought back to circuit-closing position by the movement ofthe switch lever T to its dotted line position should be notedfurthermore that when the switch Sw is in its dotted line position 64 Athe reversing switch last operated is still held in circuit-closingposition and, there'- fore', the motor J is being supplied with operatmgcurrent from the mains a Z) 0 but the entire starting resistance isinserted in the rotor circuit of the motor J, and besides, the auxiliarymotor is acting in opposition to said motor J. During this time thebrake W is held in releasing position and the brakeis only applied whenthe lever T is brought back to its normal or open-circuiting positionBrake V is shown provided with an armature X controlled by the brakemagnet Y, provided with windings Z and Z, each winding being suppliedwith current of different phase, so that strong magnetism is alwaysprovided for the brake. As will be seen, the winding Z is connected atthe point 51 to the connector for the bii1d mg-post 41 and winding Z isconnected at the point 52 to the connector for bindingpost 43, while asingle wire '53 connects both the windings Z and Z" with-contacts 47 and48, which complete the circuit to the common return main 6. I

hen the hand lever T is moved to either of its extreme positionscircuits will be com pletedto the windings D and E of the switchcontrolling resistances R and R It will be seenthat the winding D isconnected at the point 54: with the electrical connections leading tothe binding-post 4:1, while winding E is connected at the point 55"withthe electrical connections leading to the binding-post 43. A common lead38 connects both windings D and E with the common return 7) of thealternating-current mains. Itwill, therefore, be seen that differentphases of alternating current will always pass through windings D and Eno matter in which direction the motor may be rotated.

construction and arrangement of parts may be made by those skilled inthe art without departing from the spirit and scope of my invention. 1,therefore, do not desire to be limited to the exact construction hereinthis closed. 1

hat I desire to have protected by Letters Patent of the United States,and claim as my invention is 7 ml. The combination with a motor, of

-means for supplying current to said motor from a source of electricity,a second source of electricity dependent upon the motor, andmeans forcontrolling the flow Of current ()bviously, variations in the details offrom said second source to cause the same to retard the speed of theIHGLUI while the current supply is cut off from the motor.

The combination with an alternating cuirentmotor, of a sourcetofcurrentindependent of the motor circuits, and means for varying the circuit forsaid current at will. to cause said source of current to retard themotor while the latter is running on open circuit. 1 Y

3. The combination with an alternating current motor, of reversingswitches therefor, accelerating apparatus for said motor, an electricpower-consuming device, and automaticmeans associated with saidaccelerating apparatus for controlling said device to cause the same todirectly retard the action of said motor. a

4. The combination with a motor, of starting resistance therefor, meansfor varying said resistance, an external electric powerconsuming devicefor directly retarding the action of said motor when desired, and meansco-acting with said resistance-varying-means for controlling saiddevice.

5. The combination with an alternating current electric motor, ofstarting resistance therefor, means for gradually cutting out orshort-circuiting said resistance as the motor increases in speed, anexternal electric. power-consuming device, and means for controllingsaid device to cause the same to retard the action of said motor aft-erpart or all of said resistances have been re-in- Serted. v

6. In an'elevator, the combination with a car, of an alternating currentmotor and hoisting apparatus for moving the car,' a generator operatedby the motor,.accelerating apparatus for the motor, means forcontrolling said accelerating apparatus from the car, and meansco-acting with said accelerating apparatus to cause said generator tosubstantially retard said motor;

7. The combination with an electric motor, of a generator operated bysaid motor, starting resistance, means for cutting out said startingresistance to effect the acceleration of the motor, and means operableupon the reinsertion of said resistance to cause said generator tomaterially retard said motor;

8. The combination with an electric motor, of generator connected tosaid motor, accelerating apparatus for said 1notor, means co-acting withthe accelerating apparatus for causing said generator to slow down saidmotor, and a single device for controlling both the acceleratingapparatus and said slowing down means.

9, The combination with an electric motor, of sectional startingresistance therefor, electro-magnetic switch apparatusfor cutting outone or more sections of said resistgenerator to cause the same to act asan electro-dynamic brake for slowing down said motor. I

11. The combination with an electric motor, of motor-controlling means,a series wound generator directly connected to said motor, and meansco-acting with said motorcontrolling-means to cause said generator tostop the motor by producing an electrodynamic braking action thereon.

12. The combination with an alternating current motor, of a source ofalternating current supply therefor, a direct current generator havingan armature winding and a field winding, said generator being connectedto run with the motor, and means for connecting the generator windingsand cansing the generator to produce a braking eflect upon the motorwhen the current supply is cut off from the motor.

13. The combination with an alternating current motor, of an elevatormechanism driven thereby, a source of alternating current supply for themotor, a direct current generator connected to run with the motor, saidgenerator having an armature winding and a field winding, and means forconnecting said. generator windings and causing the generator to producea braking effect on the motor when the current supply is cut ofli' fromthe motor.

14. The combination with a motor, of a generator connected to run withthe motor,

said generator having an armature winding and a field winding arrangedto be connected together and to produce a braking effect upon the motorproportional in strength to the speed of the motor, when power is outcit from the motor,

15. The combination with a motor, of a series-wound generator associatedtherewith, a reversing switch for said motor, an additional reversingswitch for said generator and operated by said motor-reversing switch,and means for automatically controlling said generator to cause the sameto act as a brake for said motor.

16. The combination with a motor, of a generator connected thereto,starting resistances for said motor, electro-magnetic means forcontrolling said resistances, and a switch operated by said means forclosing the circuit of the generator to cause the same to act as a brakefor the motor.

17. The combination with a motor, of a serles-wound generator driven bysaid motor,

co-acting reversing switches for said motor current motor, of a directcurrent generator associated therewith, motorcontrolling means, and aswitch co-acting with said last-named means to close the generatorcircuit to cause the same to act as an electrodynamic brake for saidmotor.

19. The combination with an induction motor, of starting resistancesconnected to the rotor circuits, means for controlling said resistances,a direct current generator driven by said motor but normally runningfree, and means operated by said controllingmeans to close a circuit oflow resistance between the terminals of said generator to cause the sameto act as an electro-dynamic brake for said motor.

20. The combination with an induction motor, of starting resistancesconnected to the rotor circuits, electro-magnetic means, for controllingsaid resistances, a direct-cur.- rent generator connected to said motor,and a switch operated by said electro-magnetic means to close thecircuit of said generator only after part or all of said resistances areinserted inthe rotor circuit.

21. The combination with a motor, of controlling means therefor, adirect current generator associated with said motor, and

automatic means for controlling the armaure circuit of said generator toact as a brake for said motor when the circuits to said motor areopened.

22. The combination with an alternating current motor, ofa directcurrent generator associated therewith, and means for closing thecircuit of said generator when the supply current to said motor is cutoff.

23. Thecombination with an elevator car and its motor, ofmotor-controlling means, of a direct current self-exciting generator associated with said motor and running unexcited when the motor runs atfull speed and automatic means for controlling said generator toexcitethe same and assist in slowing down said motor.

24. The combination with an elevator car and its motor, ofmotor-controlling means, an electro-dynamic machine connected to saidelevator motor, and running with little retardation when the motor runsat full speed, a circuit for the saidmachine, and means for controllingsaid circuit to cause said electro dynamic machine to directly apply aload on the motor to assist in reducing the speed thereof.

25. The combination with a motor, of a generat lT, and automatic meansfor controlling the flow of current from said generator to directly?and, materially retard said motor while the motor is being brought, torest.

26. The combination with a motor, of controlling means therefor, aself-exciting direct-current generator associated with said motor, andmeans for controlling said generator to act as a brake for said motorwhen the circuits to said motor are opened. Y 27. The combination withamotor, of a series wound enerator associated therewith, and means Forautomatically controlling said generator to cause the same to run freewhile the motor is running at normal speed and to act as anelectro-dynamic brake for slowing downsaid motor.

28. The combination with a motor, an electrodynamic brake associatedtherewith, and means for automatically rendering said brakeinefiectivewhen the motor circuit is opened.

29. The. combination with a motor, of reversing switches therefor, anelectrodynamic brake, and automatic means for substantiallysimultaneously opening the reversing switches and the circuit of saidelectrodynamic brake.

30. The combination with a motor, of reversing switches for'the motor,an electrodynamic brake, a relay controlling the electric circuit of thebrake, and means whereby said relay and a reversing switch are operatedsubstantially simultaneously.

31. The combination with a motor, of a reversing switch for the motor,an electrodynamic brake, a relay controlling the circuit of the brake,and automatic means for effecting the opening of said reversing switchandv operating said relay to open the circuit of the brake substantiallysimultaneously.

32. The combination with an alternating current motor, of a generator,and means for controlling the flow of current from said generator tomaterially retard said motor while the circuit of the motor is open.

33. A motor, a generator connected to run with the motor, said"generator having an armature winding and a field winding arranged to beconnected together and to produce a brakmg effect upon the motorproportional in strength to the speed of the motor, when power is cutoff from the motor.

34. In an elevator, the combination with a car, of an alternatingcurrent motor and hoisting apparatus for moving the car, a generatoroperated by the motor, accelerating apparatus for the motor, means -forcontrollmg said accelerating apparatus from the car, and means co-actingwith said accelerating apparatus to cause said generator tosubstantially retard said motor.

The combination with :an electric motor, of a generator connected tosaid motor, accelerating apparatus for said motor, means co-acting withthe accelerating apparatus for causing said generator to slow down saidmotor, and a single device for controlling both .the acceleratingapparatus and said slowing down means,

36. An alternating current motor, a source 0f alternating current supplytherefor, a dire'ct current generator having an armature winding and afield winding connected to run with the motor, and means for connectingthe generator windings and causing the generator to produce a brakingeileet upon the motor when the current supply is cut off from the motor.

37. An alternating current motor, a source of alternating current supplytherefor, a

to run with the motor, and means for causingthe generator .to produce anelectrodynamic braking effect upon the motor. and to apply the brake tothe motor when the current is cut on from the motor.

38. The combination with an electric motor,,1of a source of'electricalsupply connected to the motor, 'a generator connected to run with themotor, said generator having an armature winding and a field winding,and means for cutting oil the electrical supply from themotor andforconnecting the armature and field windings of the generator while themotor supply is cut off.

39. The combination with an alternating current motor, of a source ofalternating current supply therefor, a direct current generator havingan armature winding and a field winding said generator being con nectedto run with the motor, and means for connecting the generator windingsand causing the generatorto produce a braking effect upon the motor wnenthe current supply is cut off from the motor.

40. The combination with an alternating current motor, of an elevatormechanism driven thereby, a source of alternating current supply for themotor, a direct current generator connected to run with the motor, saidgenerator having an armature winding ing said. generator windings andcausing the generator to produce a braking cflect on the motor when thecurrent supply is cutott from the motor.

41'. The combination with a motor, of a generatorconnected to run withthe motor, said generator having an armature winding and. a fieldwinding arranged to be connected together and to produce a brakingefi'ect t upon the motor proportional in strength to and a fieldwinding, and means for connectthe speed of the met-or, when power is cut01? from the meter 4&2. An alternating CHIU'EDK'Z motor, an elevatorineciiienism driven thereby, a source of alternating current supply forthe motor, a, direct current generator cennecteri to run with thenietorhaving an armature Winding and a field "Winding, and means forconnecting said generator windings and causing the 10 generator toproduce a braking effect on the SET; 1,005,221

motor when the current supply is cut off from the motor.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing Witnesses.

FRANK T. BROWN, CHARLES M. NISSEN.

